Ventilator breath display and graphic user interface

ABSTRACT

The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status. The user interface includes a graphic representation of a breath cycle that displays the breath cycle currently being ventilated, and is also responsive to changes in ventilation settings to assist the user in evaluation the effect of those changes on the ventilator strategy before the changes are implemented.

RELATED APPLICATIONS

This is a continuation of Ser. No. 08/818,807 filed Mar. 14, 1997, nowU.S. Pat. No. 5,881,723.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of medical equipment forrespiratory therapy and more specifically to the user interface for aventilator used for monitoring and controlling the breathing of apatient.

2. Description of the Related Art

Modern patient ventilators are designed to ventilate a patient's lungswith breathing gas, and to thereby assist a patient when the patient'sability to breathe on his own is somehow impaired. As research hascontinued in the field of respiration therapy, a wide range ofventilation strategies have been developed. For example, pressureassisted ventilation is a strategy often available in patientventilators and includes the supply of pressure assistance when thepatient has already begun an inspiratory effort. With such a strategy,it is desirable to immediately increase the pressure after a breath isinitiated in order to reach a target airway pressure for the pressureassistance. This rise in pressure in the patient airway which suppliesbreathing gas to the patient's lungs allows the lungs to be filled withless work of breathing by the patent. Conventional pressure assistedventilator systems typically implement a gas flow control strategy ofstabilizing pressure support after a target pressure is reached to limitpatient airway pressure. Such a strategy also can include programmedreductions in the patient airway pressure after set periods of therespiratory cycle in order to prepare for initiation of the next patientbreath.

As patient ventilator systems and their various components, includingsensors and control systems, have become more sophisticated, and moreunderstanding is gained about the physiology of breathing and theinfirmities and damage which form the requirements for respiratorytherapy, the number of variables to be controlled and the timing andinterrelationships between the parameters have begun to confront thecaregiver with a daunting number of alternative therapeutic alternativesand ventilator settings. Also, in such a complex environment, theinterface between the ventilator and the caregiver has often not beenadaptable to the capabilities of the operator, thus running the chanceof either limiting the choices available to a sophisticated user orallowing a relatively less sophisticated user to chose poorly from thealternatives presented. Thus, it would be beneficial if a ventilatorinterface guided the user through the setup or therapy modificationprocess, illustrating the relationship between changes, preventingincorrect or dangerous settings and sounding alarms or other audibleindications of invalid settings when something is about to done thatexceeds limits, but also allowing the advanced and sophisticated user togain access to the full range of ventilator capabilities through aninterface which both presents the various parameters and allows thevisualization of their relationships.

Clinical treatment of a ventilated patient often requires that thebreathing characteristics of the patient be monitored to detect changesin the breathing patterns of the patient. Many modern ventilators allowthe visualization of patient breathing patterns and ventilator functionand the caregiver adjusts the settings of the ventilator to fine tunethe respiratory strategy being performed to assist the patient'sbreathing. However, these systems have been, up until now, relativelydifficult to use by the unsophisticated user unless a limited number ofoptions are selected. For example, in one prior art system, only asingle respiratory parameter may be altered at a time. Moreover, thevarious respiratory parameters must often be entered into the ventilatorcontroller in a prescribed order, or, where no order is prescribed,certain orders of entry should be avoided, otherwise the intermediatestate of the machine before entry of the remaining parameters may not beappropriate for the patient. This inflexible approach to ventilatorsetup requires additional time and training if the user is to quicklyand efficiently use the ventilator in a critical care environment.

Previous systems have also been deficient in that it is often difficultto determine the underlying fault that has caused an alarms to besounded, and what controls or settings should be adjusted to cure theproblem causing the alarm. For example, prior alarm systems haveconsisted of nothing more than a blinking display or light with an alarmto alert the user that a problem existed. Similarly, many prior artsystems provided only limited assistance to a user or technician insetting the parameters to be used during treatment. For example, if atechnician attempted to enter a setting that was inappropriate for thepatient because of body size or for some other reason, the only alarmprovided may have been an auditory indication that the value was notpermitted, but no useful information was provided to assist thetechnician in entering an appropriate setting.

One problem consistently presented by prior art ventilator controlsystems has been that the user interface has offered relatively littleto guide and inform the user during the setup and use of the ventilator.Prior systems typically utilized a single visual display of theoperating parameters of the ventilator and sensed patient parameters.Alternatively, prior systems may have numerous fixed numeric displays,certain of which may not be applicable during all ventilation therapies.Even when more than one display has been provided, users typicallyreceived limited feedback, if any, from the control system indicatingthe effect that changing one particular setting had on the overallrespiratory strategy. If a parameter was to be adjusted, the displaywould change to display that particular parameter upon actuation of theappropriate controls, and allow entry of a value for that parameter.However, the user was provided with no visual cue as to how the changein the parameter value would effect the overall ventilation strategy,and thus had no assistance in determining whether the value entered forthe parameter was appropriate for the patient.

What has been needed and heretofore unavailable in patient ventilatorsis a user friendly graphic interface that provides for simultaneousmonitoring and adjustment of the various parameters comprising arespiratory strategy. Such an interface would also preferably guidesophisticated users in implementing ventilation therapies, provideguidance on the relationships between parameters as they are adjusted,allow rapid return to safe operation in the event that an undesirablestrategy was inadvertently entered, provide alarms that are easilyunderstood and corrected and present all of the relevant information inan easily understood and graphic interface. The present inventionfulfills these and other needs.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the present invention is directed to agraphic user interface system for controlling a computer controlledventilator to provide respiratory therapy to a patient. In a broadaspect of the invention, the invention includes a digital processor, atouch sensitive display screen and entry means cooperating to provide auser-friendly graphic interface for use in setting up and carrying out awide variety of respiratory therapies. The processor controls thedisplaying of a plurality of screens, including user selectable graphicon-screen buttons for setting the values of various ventilator operatingparameters for controlling the ventilator. Depending on the on-screenbutton touched, the processor causes different graphics to be displayedon the screens, provides graphic representations of the effect on theoverall respiratory strategy caused by changes to the settings, and mayalso provide displays of patient data, alarm conditions, and otherinformation.

In one preferred embodiment of the invention, the system includes theuse of a digitally encoded knob for altering selected and displayedvalues of ventilation parameters, with the acceptable values indicatedand unacceptable values alarmed and/or limited to prevent harm to thepatient. The digital encoded rotation of the knob may be analyzed by theprocessor and a magnification factor applied to the knob output toincrease the speed with which displayed values are altered. Themagnification factor may also be used in the event of an overshootcondition to assist a user in recovering from the overshoot.

In another preferred embodiment of the invention, the processor maydetect the connection of a patient to the ventilator when the ventilatoris powered-up. The processor may then, in response to such a detection,start up the ventilator using a predetermined set of ventilator controlsettings deemed to be safe for the widest possible variety of patients.

In a further preferred embodiment of the invention, the processor mayonly display ventilator control settings appropriate for a selected modeof ventilation. The ranges of values of the appropriate settings, orbounds of the ventilation, may be limited by the processor in responseto the selected mode of ventilation such that only those valuesdetermined to be appropriate are displayed, thus limiting theopportunity to select incorrect settings. Additionally, the processormay be responsive to specific values entered for certain of theventilator settings to adjust the ranges of values allowed forventilator settings dependent on the certain settings. Further, theprocessor may be programmed to require that a so called “ideal bodyweight” be entered before beginning ventilation of a patient, and thenonly ranges of values for settings that would be appropriate forventilation of a patient with that ideal body weight are displayed.

In another presently preferred embodiment of the invention, the graphicuser interface system includes at least two touch sensitive screendisplays, a plurality of manual parameter controls, including at leastone control knob that is activated upon selection of a parameter to becontrolled and displayed on the screen, and a microprocessor controllerwhich controls the logic and arrangement of the screen displays and theinterface with the ventilator. The system of the invention includesprotocols programmed into the microprocessor for entry of parameterswithin ranges predetermined to be appropriate for the patient parametersentered, alarms and other audible indications of invalid entryassociated with entries outside of the acceptable ranges of parametersor inappropriate operation such as startup with a patient connected tothe ventilator, and the ability to lock selected parameters whileallowing for user variation of other parameters.

In another presently preferred embodiment of the invention, the user isprovided a graphic interface in which the user is allowed to view andadjust a variety of alarm limits and is able to vary the levels at whichthe alarms are set off, within limits that are preset by the programmingof the microprocessor as representative of values that are not to beexceeded, either as a function of ideal body weight or generalparameters for all patients. The resultant setting of a filtered set ofalarms may then be used by the user to avoid the setting of parametersthat are likely to result in patient distress or other problems with thetherapy, while still allowing the sophisticated user to configure atherapy that is customized for the particular patient.

In one presently preferred embodiment, the invention also allows theuser an “undo” option in which a previously successful setting isreestablished after the user realizes that a series of proposed changesare likely to unworkable for the patient.

In yet another presently preferred embodiment of the invention, the useris provided with alarm indicators indicating the severity of aparticular alarm. Alarm messages are also displayed in a selected screenarea of the graphic user interface to assist the user in alarmrecognition and understanding. Each alarm message may comprise anidentifying message identifying the alarm being indicated, an analysismessage providing information about the condition that caused the alarmto be indicated, and a remedy message suggesting steps that may be takenby the user to correct the alarm condition.

In a further currently preferred embodiment of the invention, theprocessor allows the user to configure the graphic user interface toprovide a display of the current and/or proposed breath parameters and agraphic representation of the breath timing controlled by thoseparameters. Such a display allows the visualization of relationshipsbetween breath parameters, and, while parameters are being changed,provides the user with a visual representation of the effect of theproposed changes on the ventilation strategy while simultaneouslyallowing the user to view current settings, thus allowing the user tosimultaneously view “where they are now” and “where they are going tobe.”

From the above, it may be seen that the present invention represents aquantum leap forward in the user interface available for patientventilation. While assisting the sophisticated user in both visualizingthe ventilation strategy and performance of the patient on theventilator, it also guides and controls the less sophisticated user insetup and understanding of the relationships between ventilatorsettings. The invention provides these benefits while enforcingfail-safe functioning in the event of a variety of inadvertent orerroneous settings or circumstances.

These and other features and advantages of the invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, which illustrate, by way of example, thefeatures of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, where like reference numerals indicate like or similarcomponents, elements and features across the several figures:

FIG. 1 is a schematic diagram of showing a patient receiving respiratorytherapy from a ventilator system comprising a graphic user interface anda respirator constituting one embodiment of the present invention;

FIG. 2 is a schematic diagram, primarily in block form, of the varioussubsystems of of the graphic user interface shown in FIG. 1;

FIG. 3 is frontal plan view showing external details of graphic userinterface of FIG. 1;

FIG. 4 is a schematic diagram, primarily in block form, of the sequenceof display screens typically displayed by the graphic user interface ofFIG. 3;

FIG. 5 is an illustration of a ventilator startup screen displayed uponstartup of the graphic user interface of FIG. 3;

FIG. 6 is an illustration of a main controls setup screen used to setthe main control settings of the ventilator of FIG. 3;

FIG. 7 is a schematic diagram, primarily in block form, illustrating howthe adjustment of certain settings affects the applicability of othersettings used to control the ventilator of FIG. 3;

FIG. 8 is an illustration of a proposed vent settings screen including abreath diagram;

FIGS. 9A, 9B, and 9C are illustrations depicting the display of thebreath diagram of FIG. 8 dependent upon the values of the parametersrepresented by the breath diagram;

FIG. 10 is an illustration of an alarm setup screen including graphicalrepresentations of various alarms settings, acceptable alarm settingparameter ranges, and current patient data;

FIG. 11 is an illustration of the upper display screen of FIG. 3;

FIG. 12 is an illustration of a “More Alarms” display screen displayedwithin the information area of the display screen of FIG. 11;

FIG. 13 is an illustration of a “Waveforms” display screen displayedwithin the information area of the display screen of FIG. 11;

FIG. 14 is an illustration of an “Apnea Ventilation In Progress” displayscreen displayed within the information area of the display screen ofFIG. 11; and

FIG. 15 is an illustration of an “Apnea Settings” display screendisplayed within the information area of the lower display screen ofFIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a sophisticated graphic user interfaceand ventilator breath display capability that allows great flexibilityin the setup of the ventilator and visualization of the effect thatproposed changes to the ventilator setup may have on the ventilationstrategy. More particularly, the invention provides a graphicrepresentation of a breath cycle that allows the user to visuallyevaluate the effect of such changes, and also to select amongappropriate parameters a parameter to “lock” and hold constant whileother parameters are changed.

The drawings will now be described in more detail, wherein likereferenced numerals refer to like or corresponding elements among theseveral drawings.

FIG. 1 shows a patient 1 receiving respiratory therapy from a ventilatorsystem having a graphic user interface 20 connected to and controlling abreath delivery unit, or respirator 22. The patient is connected to therespirator 22 by a patient circuit comprising an inspiratory line 2, andexpiratory line 4, and a patient connection tube 6, all connected by apatient connector (not shown) of a type well-known in the art. Therespirator 22 includes a processor or controller 60 which controls thereal-time operation of the respirator 22.

FIG. 2 depicts the graphic user interface 20 of FIG. 1 in more detail.Generally, the graphic user interface 20 comprises user inputs 25, aprocessor 30 and memory 35 comprising read only memory, random accessmemory or both. The memory 30 may be used to store current settings,system status, patient data and ventilatory control software to beexecuted by the computer. The processor 30 may also be connected to astorage device, such as battery protected memory, a hard drive, a floppydrive, a magnetic tape drive or other storage media for storing patientdata and associated ventilator operating parameters. The processor 30accepts input received from the user inputs 25 to control the respirator22. The ventilation control system 20 may also include status indicators45, a display for displaying patient data and ventilator settings and anaudio generator for providing audible indications of the status of theventilator system 10.

The memory 35 and a memory 65 associated with the respirator processor60 may be non-volatile random access memory (NVRAM) for storingimportant, persistent variables and configuration settings, such ascurrent breath mode setup. Typically, during normal operation of theventilation control system 20, such an NVRAM functions similarly to atypical random access memory. If, however, a low-voltage condition isdetected, such as may occur during a brown-out or at the beginning of apower failure, the NVRAM automatically stores its data into non-volatilestorage.

The graphic user interface 20 includes an interface 32 for providingcontrol signals from the processor 30 to the respirator processor 60 ofthe respirator 22, and also for receiving signals from sensors 27associated with the respirator 22 indicative of patient condition andthe status of the respirator 22. The processor 30 of the graphic userinterface 20 may also receive input representative of various clinicalparameters indicating clinical condition of the patient 1 and the statusof the respiratory therapy from the sensors 27 in the respirator 22. Theinterface may include, for example, an ethernet connection of a RS-232serial interface. A cable 34 having an appropriate number of conductorsis used to connect the respirator 22 to an appropriate connector (notshown) of the interface 32.

A preferred embodiment of the display 50 incorporating a user interfaceis illustrated in FIG. 3. Generally, the display 50 comprises an upperdisplay 60 and a lower display 70, dedicated keys 80, 82, 84, 86, 88,90, 92, 94, 96, 98, 100, 102, 104 and knob 106. As will be described inmore detail below, additional user inputs are dynamically provided byon-screen buttons that are drawn on the upper and lower displays 60 and70. Typically, each dedicated key or on-screen button includes, withinthe outline of the button, either a graphic icon or text identifying thepurpose of the button to the user. These graphic icons or text enhancethe ease of use of what would otherwise be a confusing array of userinputs. Moreover, the use of graphic icons or text to identify thefunction of dynamically generated on-screen buttons provides forvirtually unlimited opportunities to add functions to the graphic userinterface 20 by upgrading the programming of the processor 30 as newfunctions are desired by the users of the system. Additionally, the useof graphic icons overcomes the potential problem of identifying thefunctions of a button where language comprehension may be a problem,such as the use of the ventilator in a country where English is notreadily understood.

Referring again to FIG. 3, key 80 is identified with a graphic design inthe form of a stylized padlock. Actuation of key 80 by an operator locksthe keys and buttons of the graphic user interface 20 to preventinadvertent altering of the settings of the system. Keys 82 and 84control the contrast and brightness of the displays 60, 70. Key 86 bearsa stylized graphic design representative of a speaker emitting sound,and a graphic indicative of a volume control. Thus, key 86 is easilyidentifiable as a control for altering the loudness of audible alarmsignals provided by the graphic user interface 20. Key 92 bears a “?”and actuation of key 92 activates a help system to assist a user inoperating the graphic user interface 20.

Keys 94, 96, 98 and 100 control various aspects of the ventilator, andare used by an operator to override the automatic settings of thegraphic user interface 20. When key 94 is pressed, the processor 30 ofthe graphic user interface 20 provides a signal over the 32 to theprocessor in the respirator 22 instructing the respirator processor toventilate the patient with 100% oxygen for two minutes. The processor inthe respirator 22 also starts a timer and causes the value of the timeat any given instant to be written to a memory associated with therespirator processor. When the value in the respirator memory is equalto two (2) minutes, indicating that the 100% oxygen gas mixture has beenprovided to the patient for two(2) minutes, the respirator processorcontrols the respirator 22 to stop the flow of the 100% oxygen to thepatient. If the user presses key 94 during the two (2) minute durationof the 100% oxygen ventilation, the value of the time stored in thememory is reset to “0” and timing continues for an additional twominutes. Typically, the respirator processor may be programmed torespond to any number of actuations of key 94 without prompting the userfor validation or before sounding and displaying an alarm.Alternatively, the respirator processor may be programmed to respond toonly a limited number of actuation of key 94 before sending a signalthrough the interface 32 to the processor 30 of the graphic userinterface 20 requesting the processor 30 to provide a visual prompt onthe display 50 and/or to control the audio generator 55 to sound anaudible alarm indicating that an allowed number of actuations of key 94has been exceeded.

When key 96 is pressed during an exhalation, the processor 30 controlsthe ventilator to immediately provide an inspiration. Actuation of key98 results in an extension of the expiration phase. Similarly, actuationof key 100 results in a lengthening of the inspiration phase.

Key 102 is labeled with the text “Clear” and actuation of key 102 causesproposed changes to the value of a currently selected setting, to bediscussed in more detail below, to be cleared. Key 104 is labeled withthe text “Accept.” When key 104 is touched, any proposed changes to theventilator settings are confirmed, and become the current ventilatorsettings.

Knob 106 is used to adjust the value of an individual setting selectedby pressing either keys 82, 84 and 86 or certain on-screen buttons. Knob106 is mounted on a shaft whose rotation is digitally detected by arotary encoder/decoder, such that the processor 30 receives signalsindicating not only the magnitude of the rotation of knob 106, but alsothe speed and rate of acceleration and deceleration of the rotation ofknob 106. These signals are interpreted by the processor 30 to displayallowable values for the selected setting. In one embodiment of thepresent invention, the processor 30 is responsive to the signalsindicative of the speed of rotation of knob 106 to calculate a velocitybased magnification factor dependent on how fast and how long the userturned the knob that is applied by the processor 30 to adjust theincrement of the values displayed. The processor 30 uses this magnifyingfactor to increment the displayed values in larger increments when knob106 is rotated rapidly, and incrementing the displayed values in smallerincrements when knob 106 is rotated slowly.

A common problem using rotating knobs where a magnification factor isapplied in this manner is that there is inevitable “overshoot” of thedesired value. Following an overshoot, the user must reverse thedirection of rotation of the knob. This reduces the speed of rotation ofthe knob to zero, and eliminates the magnification. Elimination of themagnification, however, results in more rotation and time to recoverfrom the overshoot. One novel aspect of the present invention is thatthe processor 30 does not reduce the magnification factor to zero whenthe knob is counter rotated, as described above. Rather, the processor30 applies a magnification factor to the counter rotation to reduce theamount of rotation of the knob 106 necessary to recover from theovershoot. The processor sets a time based limit on how quickly themagnification factor is allowed to decrease, thus ensuring that somemagnification remains during overshoot recovery.

Additionally, the processor 30 may provide signals to the audiogenerator 55 to cause the audio generator 55 to provide an audibleindication of the rotation of knob 106. For example, the audio generator55 may generate a “click” for a predetermined amount of rotation of theknob 106 or to signify that an on-screen button or dedicated key hasbeen actuated. The audio generator 55 may also provide an audio signalto the user if the maximum or minimum value of the range of values forthe selected setting has been reached, indicating that further rotationof the knob 106 will not cause any larger or smaller values to bedisplayed.

Referring again to FIG. 3, the display area of the ventilation controlsystem 20 comprises an upper display 60 and a lower display 70. Theupper display 60 is divided into four non-overlapping areas. These areasare “vital patient data” area 110, an “alarm message” area 120, an“information area” 130 and a “controls” area 140. Area 130 is amultipurpose area that may be used to display, for example only, screensdepicting current alarms, an alarm history log, real-time waveforms,measured patient data that is not otherwise displayed in the vitalpatient data area 110, quick reference information, a log of diagnosticcodes, operational time for system components, a ventilator testsummary, the current ventilator software/hardware configuration, a logof the results from running a short self test, apnea ventilationsettings and safety ventilation settings.

Similarly, the lower display 70 is divided into five non-overlappingareas. These areas are a “main settings” area 150, an “information area”160, a “controls” area 170, a “symbol definition” area 180 and a“prompt” area 190. Examples of information displayed in area 160include, but are not limited to screens displayed during ventilatorstartup and ventilator setup, apnea setup, alarm setup, new patientsetup, communications setup, date/time setup, miscellaneous setting nototherwise shown in the main settings area 150 and breath timing graphs.

It will be understood that the labeling of the four non-overlappingareas of the upper display 60 and the labeling of the fivenon-overlapping areas of the lower display 70 are not critical to thepresent invention, but are for convenience only. Thus, the areas couldhave other labels, depending on the information desired to be conveyed.

The display area also includes an alarm display area generally indicatedby reference numeral 108. The alarm display area 108 includes a highurgency alarm indicator 110, a medium alarm urgency indicator 112 and alow urgency alarm indicator 114. The alarm urgency indicators 110, 112and 114 may be light emitting diodes or any other means of providing avisual indication of an alarm. Additional indicators (not shown) mayalso be included below the alarm indicators.

Low urgency alarms are used to inform the user that there has been somechange in the status of the patient-ventilator system. During a lowurgency alarm, the low urgency alarm indicator 114 lights, an audiblealarm having a tone indicating that a low urgency alarm event hasoccurred, and an alarm message is displayed in the alarm message area120 of the upper screen 60. During a medium urgency alarm, the mediumurgency alarm indicator lights, a medium urgency audible alarm issounded, and an alarm message is displayed in the alarm message area 120of the upper screen 60. Because medium urgency alarms typically requireprompt attention to correct the cause of the alarm, the medium urgencyindicator may flash, and the audible alarm may sound repeatedly with adistinctive tone.

High urgency alarms require immediate attention to ensure patientsafety. During a high urgency alarm, the high urgency indicator 110,which may be colored red, flashes, a distinctive audible alarm issounded and an alarm message is displayed in the alarm message area 120of the upper screen 60.

Referring now to FIG. 4, the overall hierarchical structure of the userinterface comprising the keys, on-screen buttons and upper and lowerdisplay screens will be described. When the user of the ventilator turnson the power to the graphic user interface 20 and respirator 22 byactuating a power switch typically located on the respirator 22 (notshown), the processor 30 begins to power itself up by initiating a poweron self test (POST). If the user actuates a test button, also typicallymounted on the respirator 22 (not shown) during the time when the POSTis running, the ventilator will start up in a SERVICE mode. If the testbutton is not actuated, the ventilator will start up in a VENTILATORmode.

When the graphic user interface starts up in the VENTILATOR mode, thelower display 70 of the graphic user interface 20 displays theventilator startup screen 200 depicted in FIG. 5. When the ventilatorstartup screen 200 is displayed, the main settings area 150 of the lowerdisplay has two subareas; the upper subarea 152 displays the mainventilator mode settings, while the lower subarea 154 displays thevalues of the ventilator settings appropriate to the main ventilatormode settings that were in use prior to powering down the graphic userinterface 20 and respirator 22.

The control area 170 on the lower screen 70 typically contains one ormore on-screen buttons (see FIG. 8), but is blank on the ventilatorstartup screen 200, as illustrated in FIG. 5. This illustrates thedynamic nature of the various screens that are presented to the user toassist the user in selecting ventilator settings appropriate to a givenrespiratory strategy. At this stage of the startup process, no settingsother than those illustrated are presented to the user so that the usermay not inadvertently enter an inappropriate ventilator setting. Othernovel features of the display of the present invention further assistingthe user will be described below.

A message instructing the user as to what action to take next isdisplayed in the prompt area 190. As indicated by the message displayedin the prompt area, it is important that the ventilator be setup beforeattaching the ventilator to a patient. As is illustrated by displaydepicted in FIG. 5, on-screen buttons such as buttons 225, 230 and 240that are active and may be touched by the user to initiate activity aredisplayed so that the on-screen buttons appear to have a raised, threedimensional appearance. In contrast, on-screen buttons whose actuationis not appropriate on a particular screen are displayed having a flat,non-three dimensional appearance, as, for example, the on-screen buttonsdisplayed in subarea 154 of the main settings area 150.

The information area 160 of the ventilator startup screen 200 providesthe user with three on-screen buttons to choose from to initiate thenext step in completing the setup of the graphic user interface 20. Theuser may touch the SAME PATIENT on-screen button 225 followed by theoff-screen ACCEPT key 104 to set up the ventilator with the settingsdisplayed in the main settings area 150. If no previous patient settingsare stored in the memory 35, the SAME PATIENT on-screen button will notbe displayed. Alternatively, if the ventilator is being used to providerespiratory therapy to a patient different from the previously treatedpatient, the user may actuate the NEW PATIENT on-screen button 230.Actuation of the NEW PATIENT on-screen button 230 will result in thedisplay of a new patient setup screen. The user may also choose toperform a short self test (SST) of the ventilator and the graphic userinterface 20 by touching the SST on-screen button 240. The SST on-screenbutton 240 will not be displayed if the ventilator is already connectedto a patient.

The upper display 60 and the lower display 70 incorporate touchsensitive screen elements, such as, for example only and not by way oflimitation, infrared touch screen elements, to allow for actuation ofon-screen buttons, such as on-screen buttons 205, 210, 215, 220, 225,230 and 240. The touch screen elements and the processor 30 operate incoordination to provide visual cues to the user as to the status of theon-screen buttons. For example, as described previously, the on-screenbuttons are displayed in such a manner as to appear to bethree-dimensional. When one of the on-screen buttons is actuated by theuser touching the display screen with a finger, a pencil or otherinstrument, the touch screen elements detect the application of thefinger, pencil or other instrument and provide the processor 30 withsignals from which the screen location where the touch occurred may bedetermined. The processor 30 compares the determined location of thetouch with the locations of the various buttons displayed on the currentscreen stored in the memory 35 to determine the button, and thus theaction to be taken, associated with the location of the touch. Theprocessor then changes the display of the touched on-screen button tomake the button appear to be depressed. The processor may also alter thedisplay of the text incorporated into the three-dimensional on-screenbutton. For example, the SAME PATIENT text displayed on the on-screenbutton 225 normally appears as white letters on a dark or gray buttonwhen the button is in an untouched stated. When the button 225 istouched, the processor 30 may cause SAME PATIENT to be displayed asblack letters on a white button. Additionally, the prompt area 190 maychange to a white background with black letters to draw the user'sattention to the prompt area 190 when a message is displayed in theprompt area 190.

Typically, the action initiated by touching an on-screen button isobtained when the user lifts the finger, pencil or other instrument fromthe surface of the display screen. However, the processor may also beresponsive to a user sliding the finger, pencil or other instrument offthe on-screen button and onto the remaining surface of the displayscreen to reset the on-screen button in its un-actuated state and totake no further action. Thus, the action initiated by the touching ofthe on-screen button may only be obtained when the finger, pencil orother instrument is lifted from the portion of the display screen thatis displaying the on-screen button. This feature allows the user toabandon a button touch without activating the function associated withthe button in the case where the button was touched inadvertently or inerror.

When the NEW PATIENT on-screen button 230 is touched, the processor 30responds by displaying a new patient setup screen (not shown) and purgesany previously entered settings from the memory 35. The new patientsetup screen includes an IBW on-screen button for displaying andaltering the value for the ideal body weight (IBW) of the patient. Thenew patient setup screen also includes a CONTINUE on-screen button;however, the CONTINUE button is not displayed until the IBW button istouched to ensure that the user adjusts the IBW to a suitable value. TheCONTINUE button is displayed immediately after the IBW button istouched. Thus, if the value for IBW currently stored in the memory 35 isacceptable, the IBW does not need to be adjusted, and the CONTINUEbutton may be touched to accept the current value of the IBW.

When the IBW on-screen button is touched, the value for IBW currentlystored in the memory 35 of the graphic user interface 20 may be adjustedby the user by rotating the knob 106 to either increase or decrease thedisplayed value until the value for the IBW desired by the user isdisplayed. The user may then touch the CONTINUE button to store the newvalue for IBW in the memory 35. When the CONTINUE button is touched, theprocessor 30 responds by causing a vent setup screen to be displayed.Because the vent setup screen is being displayed in response to thecompletion of the new patient setup screen, the vent setup screen isdisplayed in a new patient mode, and is labeled accordingly.

The processor 30 is responsive to the entered value for the patients'IBW to determine the initial values and ranges, or bounds, of the valuesof the various ventilator settings that are appropriate for use with apatient having that IBW. For example, the range of appropriate valuesfor the various ventilator settings differ between adults and children.The processor will display only values that fall within the appropriaterange of values for selection by the user during setup dependent uponthe IBW, and will not accept values for settings that fall outside ofthe determined range. If the user attempts to enter a value outside ofthe appropriate range for that patient's IBW, the processor 30 mayprovide an audible indication of an attempt to enter an out of rangevalue and/or a prompt to the user that the value is inappropriate.

Referring now to FIGS. 6-8, the layout and functions of the vent setupscreen will now be described. Traditionally, setting up a ventilatorrequired a user to navigate through a number of confusing andcomplicated displays. A novel aspect of the present invention is thesimplification of ventilator setup by hierarchically categorizing theventilator controls and settings to minimize the number of choicesavailable to a user on any one screen. The vent setup sequence used toconfigure the ventilator comprises two display phases. These two phaseshave been designed to simplify setup of the ventilator by groupingventilator settings in logically arranged groups. Further, the settingsentered during the first phase determine the settings presented to theuser during the second phase. In this manner, only those ventilatorparameters that are appropriate for the mode settings entered during thefirst phase are displayed. Additionally, the ranges of values, orbounds, of the displayed settings may be further limited as appropriatedepending on the proposed ventilator mode and settings. Moreover, sincesome ventilator parameters may be dependent on the values selected forcertain other ventilator parameters, the ranges of values for thedependent ventilator parameters may be limited in accordance with thesettings of those independent ventilator parameters. In this manner, theuser is presented only with those settings that are appropriatedepending on settings already entered by the user. Such a hierarchicalsequencing and presentation are useful in preventing the inadvertententry of inappropriate ventilator settings.

Once a value for IBW has been entered, the subsequent phases of the NewPatient Setup process are similar to the “Vent Setup” sequence ofscreens which may be accessed at any time during normal ventilation bytouching button 321 (FIG. 8). For example, in the first phase of NewPatient Setup, a screen is displayed entitled “New Patient Setup”instead of “Current Vent Setup” and is preceded by a screen presentingthe proposed setting for IBW. Similarly, in the second phase, the titleof the screen is “New Patient Settings” instead of “Current VentSettings.” Accordingly, the following discussion address the “VentSetup” sequence.

When the vent setup screen is first activated, or following the IBWscreen utilized during the new patient setup procedure described above,the Main Controls phase depicted in FIG. 6 is displayed. In the MainControls phase, only buttons 302, 304 and 306, representing the maincontrol settings, are visible in the information area 160 of the lowerdisplay screen 70. As shown in FIG. 8, however, the values for thecurrently selected main controls continue to be displayed in area 152,and the currently selected settings are displayed in area 154 of themain settings area 150 of the lower screen 70. The values displayed inareas 152 and 154 remain visible at all times during ventilation setup;thus it may be assumed that they are displayed unless specific referenceis made to the display of different information in areas 152 and 154.When the main controls screen is being displayed during the “New PatientSetup” sequence, the on-screen buttons in area 154 of the main settingsarea 150 are displayed with a flat, non-three dimensional appearance,indicating that they cannot be actuated. During normal ventilationhowever, the on-screen buttons in area 154 may always be actuated by theuser; thus they are displayed with a raised, three-dimensionalappearance during normal ventilation.

As depicted in FIG. 7, the present invention decomposes the traditionalmode setting into a simple mode plus separate “mandatory type” and“spontaneous type” settings. There are three modes: “A/C”, orassist/control mode; “SIMV” or synchronous intermittent mandatoryventilation; and “SPONT”, for spontaneous respiration. Dependent on themode and type selected, the processor 30 will display only thosesettings appropriate to that mode and mandatory type. For example, ifthe user selects “A/C” mode and “PC” mandatory type, the processor 30will display on-screen buttons for changing ventilator settings relatedto pressure control of the ventilation. Similarly, selecting “SPONT”mode and “PS” spontaneous type results in the display of on-screenbuttons for changing ventilator settings related to pressure support.

Referring again to FIG. 6, Button 302 is labeled with “Mode”; Button 306is labeled with “Mandatory Type”; and Button 306 is labeled with“Trigger Type.” Each of the buttons 302, 304 and 306 also display thesetting currently selected for each of the main control settings. Forexample, button 302 displays “A/C” indicating that assist/control modeis selected. Alternatively, where SIMV or SPONT modes are currentlyselected, button 302 will display either SIMV or SPONT as appropriate.When either SIMV or SPONT modes are currently selected, a fourth button,button 308 (not shown) labeled with “Spontaneous Type” may also bedisplayed. Further, when the mode is set to SPONT, a message may bedisplayed below button 304 indicating that the value displayed on button304, “Mandatory Type,” applies to manual inspiration only.

As with others of the buttons used to make changes to the values ofvarious operational parameters used by the processor 30 to control therespiratory therapy of a patient, the main control settings on thecurrent vent setup screen are set by touching the desired one of thedisplayed buttons 302, 304, 306 or 308 (not shown), and then rotatingknob 106 until the desired value is displayed. When the desired valuefor the setting is displayed, the user may provisionally accept andstore that value in the memory 35 by touching the continue button 310.Alternatively, if more than one main control setting needs to be changedby the user, the user may defer touching the continue button 310, andmay instead select among the other buttons to change the values of adifferent main control settings. The user may, if so desired, change thevalues of each of the main control settings. When the user has changedall of the desired main control settings, the changed values for each ofthe main control settings may be provisionally accepted, pendingcompletion of the second phase of the ventilator setup procedure, andstored in the memory 35 simultaneously by touching the continue button310. Thus, the values for the main control settings may be accepted andstored in a batch, rather than one setting at a time. This isadvantageous in that entry of multiple settings is easier and less timeconsuming. Batch entry is also useful in that all of the proposed valuesfor the main control settings are displayed, and may be checked forentry errors by the user before being committed storage in the memory35.

When the continue button 310 is touched, the first phase of ventilatorsetup is complete and the second phase begins. In the second phase ofventilator setup, the processor 30 displays a proposed vent settingsscreen 320 to prompt the user to complete the vent settings phase of thesetup procedure, as depicted in FIG. 8. The proposed vent settingsscreen is displayed in the information area 160 of the lower display 70(FIG. 3). This screen includes a display 326 of the main controlsettings set in the first phase described above, and an area 328 where aplurality of buttons are displayed. The buttons displayed in the area328 are for setting the values for particular ventilation parametersthat are appropriate to the main control setting. Thus, the buttonsdisplayed in area 328 are dependent upon the values selected for themain control settings in the first phase of the ventilator setup. Thisdisplay of only those buttons whose settings are appropriate to theirassociated main control settings simplifies the display, thus aiding theuser in setting up the ventilator and preventing inadvertent errors dueto user confusion.

As with the main settings screen displayed during the first phase of thevent setup procedure, the user may select a parameter to change bytouching one of the on-screen buttons, such as the “PI” on-screen button352. When the user touches button 352, the button appears to bedepressed, and may change color and text contrast as described above.The user then adjusts the value of the setting by turning knob 106 (FIG.3) until the desired value is displayed on the button 352. If the useris satisfied with the value entered for button 352, and the otherdisplayed values, the user may touch the PROCEED button 356, followed bythe ACCEPT key 104 (FIG. 3) to complete the vent setup procedure.Alternatively, the user may touch another one of the on-screen buttons,such as the “f” on-screen button 350. When button 350 is touched, button352 “pops” up, indicating that button 352 is no longer selected, andbutton 350 appears to become depressed. An audible indication that thebutton is touched, such as a “click” may also be provided. In thismanner, the values for all of the settings displayed may be changed oneafter another if desired, or only certain of the settings may bechanged, as desired by the user. The user then may configure theventilator to operate in accordance with all of the changed settings atonce in a batch fashion by touching the PROCEED on-screen button 356,followed by pressing the off-screen ACCEPT key 104.

FIG. 8 further illustrates additional aspects of the graphical featuresprovided by the user interface 20 that assist the user in setting up andoperating the ventilator. As depicted in FIG. 8, the main settings area152 displays the currently active main settings. These settings areeasily compared with the main settings entered during the first phase ofsetup that are now displayed on the proposed vent settings screen inarea 160. For example, as illustrated in FIG. 8, the ventilator iscurrently setup to ventilate in the SIMV mode, and the user hasprovisionally changed the mode to A/C, as indicated in the display 326.Another aspect of the invention is the visual prompt provided to a userthat a particular setting has been changed. This aspect is illustratedby the change in the font used to display the value of the setting for“P_(I)”, where the value “15.0” is displayed in italics, indicating thatthis value has been changed, compared to the normal font used to displaythe value “16” for “f”, indicating that this value has not been changed.

If any of the main settings were changed during the first phase of thevent setup procedure were changed, the PROCEED on-screen button 356 isdisplayed on the proposed vent settings screen 320. Similarly, if noneof the main settings were changed, the PROCEED on-screen button is notdisplayed until one of the settings displayed during the second phase ofthe vent setup procedure is changed. If the user is satisfied with thevalues for the settings that have been entered, the user may touch thePROCEED on-screen button 356. The user may then complete configurationof the ventilator settings, replacing the current vent settings with theproposed settings, by pressing the off-screen ACCEPT key 104. Theoff-screen placement of the ACCEPT key 104 ensures that no inadvertentchanges are made to the ventilator settings.

If the processor 30 determines that the vent setup screen has beenactivated within a predetermined short period of time, for example,within 45 minutes of the most recent time the vent setup screen was usedto change values of the ventilator settings, the processor 30 maydisplay a PREVIOUS SETUP button on the main settings screen 300 (FIG.6). The processor 30 removes this button from the screen if any changesare made using the screen. If the user touches the PREVIOUS SETUP button(not shown) on the main settings screen, a screen similar to the secondphase display depicted in area 160 (FIG. 8) is displayed, showing valuesfor the settings as they were immediately prior to the last settingchange made using the vent setup screen. The on-screen settings buttonsare all displayed in the flat, non-three dimensional state, indicatingthat they cannot be adjusted. A prompt message is displayed in area 190explaining that accepting the displayed values will result in the entireprevious setup being restored, including old alarm and apnea settings.The previous setup may be re-instated by the user by touching thePROCEED button 356, followed by pressing the ACCEPT key 104. Thisfeature of the present invention allows a user to quickly restore theventilator to the settings state it was in prior to a major setup changein the event that the altered ventilation strategy is not successful. Atime lime is placed on the availability of the previous settings toavoid the possibility of re-imposing the settings when the patient'scondition may have changed substantially. Individual changes to settingsmay be made to settings in the period following a major settings changewithout invalidating the settings stored for the previous setup.However, batch changes, that is, the changing of more than a singlesetting at a time, results in the stored previous settings beingreplaced with the most recent set of settings. This provides the userwith the ability to fine tune the settings made during the major changewithout losing the ability to “UNDO” all of the major changes and returnto the previous settings.

Referring again to FIG. 8, the proposed vent settings screen 320 alsoincludes a graphical representation, or breath diagram 330, of thebreath cycle that will be provided to the patient based on the settingsentered by touching the buttons displayed in area 328 and adjusting theresulting displayed values using the knob 106, as described above. Thebreath diagram 330 includes a time line 332 that is displayed for scalepurposes only, an inspiration bar 334 indicating the portion of thetotal breath duration during which inspiration will take place, anexpiration bar 336 indicating the portion of the total breath durationduring which expiration will take place, an inspiration/expiration ratiodisplay 338 and a total breath time display 346. Besides the graphicalrepresentation of the duration of the inspiration and expirationportions of the total breath cycle, text representing the selected valuefor the durations may be displayed in the respective bars 334 and 336.For example, the inspiration phase of the breath is set to require 1.0seconds and the expiration phase is set to require 2.75 seconds. Thecolors or shading of the inspiration bar 334 and the expiration bar 336are preferably different to facilitate a user distinguishing betweenthem. For example, the inspiration bar 334 may be shaded dark with whitetext, indicating that the breath timing parameter is “locked”, while theexpiration bar 336 may have grey shading and black text. It will beunderstood that this color scheme is only one example of a variety ofcolor schemes that may be used to enhance the graphical representationof the breath cycle to provide a readily comprehensible display ofeither the current status of the ventilation or to assist a user inevaluating the effects of proposed changes to the ventilator settings.

Lock on-screen buttons 340, 342 and 344 are displayed above the timeline 332 and display the lock status of the settings for the inspirationbar 334, the inspiration/expiration ratio 338 and the expiration bar 336respectively. The user may change the lock status of the settings byselecting and touching one of the lock icons 340, 342, 344. For example,lock button 340 displays a graphical representation of a closed, orlocked, padlock, while lock buttons 342 and 344 display graphicalrepresentations of open, or unlocked, padlocks. Touching lock button 340will result in the lock button changing to the open, or unlocked state.Similarly, touching lock buttons 342 or 344 will result in the touchedlock button changing to the closed, or locked, state. The effect of the“locked” setting is that the setting will not be automatically changedin accordance with a subsequent change in the breath rate parameter,while both of the settings for the “unlocked” parameters, here, theexpiration time and the ration of inspiration to expiration, will bechanged.

The display of the lock buttons is dependent upon the selected maincontrol settings. For example, in the representative example depicted inFIG. 8, main control setting Mandatory Type is set to “PC”, thus causingthe lock buttons to appear; if the Mandatory Type is set to “VC”, thelock bottoms would not be displayed. When the Mandatory Type is “PC”,only of the of the three “breath timing” settings, T_(I), T_(E) or I:Eis displayed. T_(I) is set by touching the on-screen button labeledT_(I), and adjusting the knob 106 until a desired value is displayed.The value will be displayed both on the on-screen button T_(I), and inthe inspiration bar 334 of the breath diagram 330. Because the value forT_(I), is locked, as evidenced by the closed lock button 340, and thedark shading of the inspiration bar 334, changes to the breath rate donot result in a change to the inspiration time; only the expirationtime, inspiration/expiration ratio and the total breath time change. Ifanother time parameter, such as TE was locked, changes to the rate wouldnot affect T_(E), but T_(I) and the inspiration/expiration time ratiowould change.

The above described relationship is apparent from FIGS. 9A-C. In FIG.9B, the breath rate has been reduced; thus, the total breath time isincreased, as indicated by the value in total time display 344 b. Sincethe value for the inspiration time was locked, the relative length ofthe inspiration bar 334 b did not change, while the relative length ofthe expiration bar 336 b increased. A novel aspect of the presentinvention evident from the display depicted in FIG. 9B is the change inthe location of the total breath time display 344 b. In FIG. 9A, thetotal breath time display 344 a is located below the time line 332 a. InFIG. 9B, the expiration bar 336 b has grown larger because of theincreased breath time to the extent that the total breath time display344 b has approached the end of the time line 332 b. The processor 30maintains the location of each of the graphical features of the displaysin the memory 35, and constantly assesses whether the display of agraphical feature, such as the breath diagram 330, on-screen buttons ortext may possibly collide or overlap. In the case depicted in FIG. 9B,the processor 30 determined that the total breath time display 344 bwould be displayed sufficiently close to the end of the time line 332 bthat the total breath time display 344 b would interfere with thedisplay of the numerical scale of the time line 332 b. Accordingly, theprocessor caused the total breath time display 344 b to be displayedabove the time line 332 b to avoid such interference. It will beunderstood that the use of the total breath time display 344 b is forpurposes of example only. Any of the text or numeric values displayed inconjunction with the breath timing diagram 330 may be displayed asnecessary to prevent interference with other graphical elements.

The processor 30 is also responsive to the values of the setting tochange the scale of the time line 332 when appropriate. As depicted inFIG. 9C, the total breath duration 344 c has been increased again, andis now greater than the previous scale of the time line 332 c.Accordingly, the processor 30 has caused the time line 332 c to bedisplayed with a larger scale. As the scale of the time line 332 cenlarges, the relative lengths of the inspiration and expiration bars334, 336 also change. As was described above, if the relative length ofthe inspiration bar 334 c becomes too small to allow the display of thevalue of the inspiration time setting within the bar as depicted, theprocessor may cause the value to be displayed either above, below or tothe left of the time line 332 c in the vicinity of the inspiration bar334 c.

One advantage of a preferred embodiment of the invention is that themain control settings are displayed on both the vent setup screen and inthe main setting area of the 152 of the lower display 150. Thus a usermay adjust the main settings using either screen. However, it isparticularly advantageous to make adjustments to the main controlsettings using the vent setup screen because only one main setting at atime may be changed in the main settings area 152, while multiplechanges may be made in the vent setup screen and then accepted by theuser and stored in the memory 35 of the graphic user interface 20 by theuser as a batch.

Referring now to FIG. 10, the alarm setup screen will be described.Touching the “Alarms” button 215 (FIG. 5) on the lower screen 70 causesthe processor 30 to display the alarm setup screen 400. The alarm setupscreen 400 displays graphical representations for those user-adjustablealarms that are appropriate given the values selected for the maincontrol settings. Thus, a user may be presented only with alarm settingsrequired by the ventilation strategy already entered and stored in thememory 35 of the graphic user interface 20. This facilitates setup andprevents errors or omissions due to information overload given therelatively small size of the information display area 160 on the lowerscreen 70 of the graphic user interface 20.

Ease of use is further enhanced in that each graphical representation410 a, 410 b, 410 c, 410 d and 410 e of an alarm includes a label 415identifying the patient data parameter associated with the alarm and adisplay 420 of its current value. The value for the alarm settingassociated with particular patient data parameter setting is displayedon an on screen button 425. To further enhance the usefulness andcomprehensibility of the graphical representations 410 a, 410 b, 410 c,410 d and 410 e, the processor 30 causes the alarm on-screen button 425to be displayed at a location along the graphical line that isproportional to the value of the setting with respect to total length ofthe graphical line.

The user may adjust the setting of each of the displayed alarm settingsby touching a selected alarm on-screen button, such as alarm button 425,and then rotating the knob 106 (FIG. 3) until the desired alarm settingis displayed on the alarm button 425. As the value for the alarm settingis changed by rotating the knob 106, the processor changes the positionof the alarm button 425 along the graphical line, providing a visualdisplay of the change to the user. The position of the displayed patientdata parameter 420 is similarly adjusted.

Certain alarm settings may also be turned off so that no alarm soundsfor selected control settings. One possible display of an alarm in theoff state is shown by the location and display of the alarm on-screenbutton 425 b.

Some patient data parameters may require the setting of both upper andlower alarm limit values defining a range of acceptable values beyondwhich a user desires an alarm to be given, as is depicted by thegraphical representation 410 c. Alternatively, as depicted by thegraphical representation 410 d, a lower limit alarm may be turned off bythe user, while setting an upper limit alarm to a selected value.Similarly, the upper limit alarm may be turned off while a value for alower limit alarm is set. When all of the alarms are set, the user maystore the values for one, or all of the alarm settings in a batch mannerby touching the PROCEED button 430 followed by pressing the off-screenACCEPT key 104.

Referring now to FIG. 11, one exemplary layout of the upper displayscreen 60 of the graphic user interface 20 will now be described. Asdescribed above, the upper display screen 60 includes fournon-overlapping areas 110, 120, 130 and 140. Generally, the upperdisplay screen 60 provides a user with information regarding the stateof the current ventilation therapy. Vital patient information isdisplayed in the vital patient information area 110. The informationdisplayed in area 110 is always displayed when ventilation is inprogress, even while the lower display screen 70 is being used to modifythe settings controlling the ventilation. One novel aspect of thepresent invention is the display of the current breath type and breathphase in the breath type area 525 shown located in the upper left cornerof the vital patient data area 110. In addition to the “CONTROL” breathtype displayed, the ASSIST OR SPONT breath types may be displayed inaccordance with the values for the main settings set as described above.The breath phase, that is, inspiration or expiration, is indicated byalternately reversing the display of the breath type in the breath typearea 525. For example, the text displayed in the breath type area 525may be displayed as black letters on a white background during theinspiration phase, and as white letters on a black background during theexpiration phase.

It is not unusual during the course of a ventilation treatment sessionfor values of monitored parameters to exceed the limits set for thevarious alarms that may be active during the session. The processor 30receives signals from the sensors 27 (FIG. 2) for a variety of monitoredparameters through the interface 32 and compares the values of thoseinputs to the values associated with the alarm settings stored in thememory 35. When the processor determines that the value of an inputviolates the value or values for the limit or limits for a particularalarm setting associated with that input stored in the memory 35, theprocessor 30 may cause an audible alarm to be sounded, and displays atext prompt identifying the monitored parameter, the cause of the alarmand a proposed course of action to correct the out of limit condition inthe alarm messages area 120. If an event occurs that is potentiallyharmful to the patient, the processor 30 may also control the ventilatorto abort delivery of the current breath until a user may intervene andcorrect the condition causing the alarm.

Many alarm conditions, however, may exist that do not require immediatecorrection, but are useful to evaluate the course of the respiratorytreatment. Accordingly, all alarms are accumulated in an “Alarm Log”that is a chronological listing of all alarms that have occurred andwhich may be reviewed in area 130 of the upper screen 130 (FIG. 3) atany time during or after respiratory treatment. If, for some reason, thealarm log contains records of alarm conditions than may be convenientlystored for latter viewing, the processor 30 may cause the oldest alarmrecords to be deleted, and thus they will not be available for viewing.

If multiple alarm conditions occur during the course of treatment, thenumber of alarm messages may exceed the display area available in thealarm message display area 120. The processor 30 may display thosealarms having the highest priority in the display area 120, scrollingalarms having a lower priority off the screen. The user may reviewalarms having a lower priority by touching the “More Alarms” button 510displayed in the controls area 140. The scrolled alarm messages aredisplayed in the information area 130 of the upper screen 60. When the“More Alarms” button 510 is touched, the upper screen 60 is temporarilyre-arrange to merge areas 130 and 120 into a combined and larger activealarms display, as depicted in FIG. 12. Touching the “More Alarms”button 510 again causes the processor 30 to redisplay the default screendisplay depicted in the FIG. 11.

Each alarm message 602 (FIG. 12) includes three messages to assist theuser in correcting the cause of the alarm. A base message 604 identifiesthe alarm. As will be described more fully below, the user may touch thealarm symbol to display a definition of the alarm symbol in the symboldefinition area 180 of the lower screen 70 (FIG. 3). An analysis message606 gives the root cause of the alarm, and may also describe dependentalarms that have arisen due to the initial alarm. A remedy message 608suggest steps that can be taken by the user to correct the alarmcondition.

As illustrated above, the processor 30 may be responsive to usercommands to display various kinds of information in the information area130. For example, FIG. 11 depicts one possible embodiment of the upperscreen 60 having five on-screen buttons for causing various informationand data to be displayed in the information area 130. Touching“Waveform” button 515 causes the processor 30 to display a graphicalplot of the data pertinent to the respiratory therapy being given to thepatient. Similarly, touching the “More Data” button 530 results in theprocessor 30 displaying a screen including a variety of data that may beuseful to the user in assessing the status of the patient and theprogress of the ventilation therapy. It will be understood that thepresent invention is not limited to including only the five on-screenbuttons depicted in FIG. 11. Because the on-screen buttons areimplemented by the processor 30, with suitable programming the processor30 may be enabled to display different or additional on-screen buttonsand perform actions in response to their actuation.

Touching the “Waveform” button 515 displays a waveform display screen550 as illustrated by FIG. 13. This display allows for real-timeplotting of patient data in the tow plots areas 552 and 554. Differentplots may be displayed in each of the plot areas 552 and 554. A plotsetup screen (not shown) may be accessed by the user by touching the“Plot Setup” button 556. The user may select among plots of pressureversus time, volume versus time, flow versus time and pressure versusvolume.

The waveform display screen 550 also includes a “Freeze” button 558 forfreezing any waveform that is currently being plotted in either plotarea 552 or 554. Touching button 558 causes a flashing “Freezing”message to be displayed until the current plot is completed and preventsany changes being made to the waveform display screen 550 by causing thevarious buttons controlling the scale of the displays, as well asbuttons 556 and 558 to disappear. The only visible button is an“Unfreeze” button (not shown). When the current plot is complete,plotting stops and the on-screen buttons reappear.

Other displays may also be accessed by touching the on-screen buttonsdisplayed in the controls area 140 of the upper screen 60. For example,touching the “Alarm Log” button 525 causes a screen listing all of thealarm events up to a predetermined maximum number of alarms, includingthose that have been corrected by the user, that have been soundedduring therapy. Touching the “More Screens” button 520 causes thedisplay of a set of additional on-screen buttons giving access toadditional data not otherwise presented on the main display screens.This feature provides a flexible way to add new features and screenswith minimal impact on the overall design of the graphic user interface.

In some modes of operation, the respirator processor 60 (FIG. 2) isresponsive to signals received from a sensor 27 in the ventilator toprovide inspiration. In this manner, the inspiration may be providedwhen the patient begins to draw a breath in, which is sensed by thesensor and results in the respirator processor 60 causing the ventilatorto provide an inspiration. The respirator processor 60 may be programmedto monitor the rate at which a patient triggers the sensor, and, whenthat rate falls below a predetermined number of breaths per minute, thevalue of which may be stored in the memory 65 (FIG. 2), the respiratorprocessor 60 sends a signal through the interface 32 to the processor 30of the graphic user interface 20. In response to this signal, theprocessor 30 displays an “Apnea Ventilation In Progress” screen 600 inarea 130 of the upper display 60, as depicted in FIG. 14. A variety ofinformation may be displayed on this screen to inform the user of thestatus of the patient and the ventilation. For example, the main controlsettings and the ventilation settings currently active may be displayedalong with a message indicating that apnea ventilation is in progress.Simultaneously, the respirator processor 60 switches to “Apnea” mode andprovides breathing assistance to the patient.

When the respirator processor 60 automatically institutes “Apnea” modein response to a lack of inspiration by the patient being treated, therespirator processor 60 controls the apnea ventilation using values ofvarious settings entered by the user from an apnea setup screen 650 thatmay be displayed in the information area 160 of the lower screen 70 asdepicted in FIG. 15 by touching the “Apnea” on-screen button 322 on thelower screen 70 of the graphic user interface 20. One useful feature ofthe manner in which the processor controls the displays of the graphicuser interface is illustrated in FIG. 15. As is shown, the values forthe main control settings and the on-screen buttons for setting theventilation settings appropriate for those main control settings for theventilation in process when “Apnea” mode was entered are displayed inareas 152 and 154 of the lower display screen (FIG. 5). Additionally,the current apnea settings are displayed in the information area 160,along with on-screen buttons which can be actuated in concert with theknob 106 to adjust the apnea settings.

Referring again to FIG. 5, another novel aspect of the present inventionwill now be described. The lower display screen 70 includes an area 180in which the processor 30 may display a variety of messages to assistthe user in setting up the graphic user interface. These messages may bedifferent from, or in addition to prompts displayed by the processor 30in the prompt area 190 of the lower display screen 70. One possible useof the area 180 is to provide a textual definition of a graphic symbolidentifying a on-screen button. For example, when a user touches the“Waveform” on-screen button 515 on the upper display screen 60 (FIG.11), the text “Waveform” may be displayed by the processor 30 in thedisplay area 180. This feature provides the user with an easilyaccessible means to determine the functionality of any of thegraphically identified on-screen buttons on either the upper or lowerdisplay screens 60, 70 while allowing the elimination of textualinformation from the displayed on-screen button to simplify the display.

It is generally an unsafe practice to power-up a ventilator with apatient already attached because the ventilator may attempt to ventilatethe patient in a manner which would be harmful to the patient. Therespirator processor 60 is responsive to detection of a such a conditionto start an “Safety PCV” ventilation mode and to send a signal to theprocessor 30 of the graphic user interface 20 to sound an alarm. In thismode, the respirator processor 60 controls the respirator 22 using apre-determined set of ventilator setting in pressure-control mode. Thesepre-determined settings are selected to safely ventilate the widest setof possible patients. Once the new patients, or same patient setupprocess is completed as described above, the processor terminates the“Safety PCV” mode, and begins ventilating the patient in accordance withthe newly entered settings.

From the above, it will be appreciated that the present inventionprovides important new capabilities in the display of a graphicrepresentation of a breath cycle for use in evaluating changes toventilation parameters while using a graphic user interface. Whileseveral forms of the invention have been illustrated and described, itwill also be apparent that various modifications can be made withoutdeparting from the spirit and scope of the invention. Accordingly, it isnot intended that the invention be limited, except by the appendedclaims.

We claim:
 1. A ventilator controller for a ventilator system,comprising: a display for displaying a plurality of ventilator relatedparameters; an interface for enabling a user to cause said display toinitiate a display of a listing of said plurality of ventilator relatedparameters and enabling the user to selectively assign values for atleast one of said plurality of ventilator related parameters in thelisting; and a user input device for causing said display to display agraphical representation of said plurality of ventilator relatedparameters and parameters of a breath cycle that is to be provided to apatient for the ventilator calculated from the assigned values of theparameters, and wherein the graphical representation of said pluralityof ventilator related parameters and the ventilator parameters of thebreath cycle that is to be provided to the patient comprises: a timescale representing the total duration of the breath cycle; aninspiration image disposed on the time scale; and an expiration imagedisposed on the time scale, adjacent to, but not overlapping, theinspiration image.
 2. The ventilator controller of claim 1, wherein saidinterface comprises a touch screen display.
 3. The ventilator controllerof claim 1, wherein said user input device comprises an input icon onsaid touch screen display.
 4. The ventilator controller of claim 1,wherein said user input device comprises an off-screen selector device.5. The ventilator controller of claim 2, wherein said touch screendisplay provides an image that the user can select to initiate thedisplay of the listing.
 6. The ventilator controller of claim 1, whereinsaid interface includes a touch screen display and at least oneoff-screen device to initiate the display of the listing.
 7. Theventilator controller of claim 1, wherein said interface enables theuser to selectively change at least one of the values assigned for saidplurality of ventilator related parameters and the ventilator controllerautomatically updates other ones of the values of the displayedparameters when such a change is made.
 8. The ventilator controller ofclaim 1, wherein said listing comprises a menu of ventilator relatedparameters selected by the user.
 9. The ventilator controller of claim1, wherein said listing comprises a graphic depicting the listing ofventilator related parameters.
 10. The ventilator controller of claim 9,wherein the inspiration image comprises a graphic representation ofinspiration duration and the expiration image comprises a graphicrepresentation of expiration duration, the inspiration and expirationdurations being calculated from said values of the parameters.
 11. Theventilator controller of claim 1, wherein said graphical representationfurther comprises a displayed value of a total breath durationcalculated from said values of the parameters.
 12. The ventilatorcontroller of claim 10, wherein said graphical representation furthercomprises a displayed value of a ratio of the inspiration duration beingcalculated with respect to the expiration duration being calculated. 13.The ventilator controller of claim 12, wherein said graphicalrepresentation further comprises an inspiration time value calculatedfrom said values of said parameters displayed in association with thegraphic representation of the inspiration duration calculated, and anexpiration time value calculated from said values of said parametersdisplayed in association with the graphic representation of theexpiration time calculated.
 14. The ventilator controller of claim 12,wherein the graphic representation of the inspiration duration is aninspiration bar and the graphical representation of the expirationduration is an expiration bar, the inspiration and expiration barshaving lengths proportional to values of the inspiration and expirationtime values and the time scale.
 15. The ventilator controller of claim14, wherein the inspiration time value is displayed within theinspiration bar if the length of the inspiration bar is sufficient toallow the inspiration time value to be displayed within the inspirationbar and the expiration time value is displayed within the expiration barif the length of the expiration bar is sufficient to allow theexpiration time value to be displayed within the expiration bar.
 16. Theventilator controller of claim 15, wherein the inspiration time value isdisplayed adjacent to the inspiration bar if the length of theinspiration bar is not sufficient to allow the inspiration time value tobe displayed within the inspiration bar and the expiration time value isdisplayed adjacent to the expiration bar if the length of the expirationbar is not sufficient to allow the expiration time value to be displayedwithin the expiration bar.
 17. A touch screen interface for aventilation system, comprising: a touch screen display for displaying aplurality of ventilator related parameters for enabling a user toselectively assign values for any of the parameters utilizing touchscreen techniques, and for displaying a breath diagram in associationwith the ventilator settings screen on the touch screen, the breathdiagram being generated according to the selected values of theparameters, and wherein the breath diagram comprises a time scalerepresenting the total duration of a breath cycle that is to be providedto a patient, an inspiration portion disposed on the time scale, and anexpiration portion disposed on the time scale, adjacent to, but notoverlapping, the inspiration portion.
 18. The touch screen interface ofclaim 17, wherein the breath diagram further comprises a displayed valuefor a complete breath cycle, the displayed value being calculated fromthe selected values of the parameters.
 19. The touch screen interface ofclaim 17, further comprising: a memory for storing programminginstructions, display data and the selected values of the parameters;and a processor connected to the memory and the touch screen, theprocessor being responsive to the means for enabling the user toselectively assign values for any of the parameters displayed on thetouch screen to generate the breath diagram.
 20. The touch screeninterface of claim 19, wherein the breath diagram inspiration andexpiration portions each have a length calculated by the processor inresponse to the selected values of the parameters.
 21. The touch screeninterface of claim 20, wherein the inspiration portion length and theexpiration portion length are displayed in proportion to the time scale.22. The touch screen interface of claim 17, wherein the processordetermines a display length for a value of the inspiration time anddisplays the value for the inspiration time within the inspirationportion if the display length for the value of the inspiration time isless than the length of the inspiration portion, otherwise the value forthe inspiration time is displayed adjacent the inspiration portion. 23.The touch screen interface of claim 20, wherein the processor determinesa display length for a value of the expiration time and displays thevalue for the expiration time within the expiration portion if thedisplay length for the value of the expiration time is less than thelength of the expiration portion, otherwise the value for the expirationtime is displayed adjacent the expiration portion.
 24. The touch screeninterface of claim 21, wherein the processor is responsive to changesinput by the user in the selected values of the ventilator parameters toadjust the lengths of the inspiration portion and the expirationportions and to display the adjusted inspiration and expiration portionsas the changes are made by the user prior to entering the changes. 25.The touch screen interface of claim 21, wherein one of the inspirationand expiration portions may be locked by the user such that the displayof the locked portion remains unchanged while the display of theunlocked portion changes in response to changes in the selected valuesof the ventilator parameters.